A conventional gas circuit breaker is disclosed in, for example, Patent Literature 1 (see FIG. 3). This gas circuit breaker is incorporated in a housing filled with insulation gas, and configured rotationally symmetrically around a central axis line. A pair of holding members is arranged around the central axis line, which holds a pair of contact rings (fixed contacts) formed of a wear-resistant metal material. The pair of contact rings is formed in a funnel shape with respect to the central axis line, arranged at a predetermined interval in the central axis line direction in a manner that a diameter is decreased toward a direction in which the contact rings approach to each other. The pair of contact rings is formed of, for example, an elastically deformable member in which a plurality of slits is formed in a radial fashion with respect to the central axis line. A pair of holding tools is attached to side surfaces of the pair of contact rings facing each other. A pair of first covering members is attached and fixed to distal ends of the pair of holding tools by a pair of second covering members. A movable contact moves reciprocally in the center axis direction between a state where the pair of contact rings is brought into contact with an outer diameter surface of the movable contact (a current supply position) and a state where the pair of contact rings is separated from the movable contact (a current cutoff position).
In this conventional gas circuit breaker, at the time of cutting off a current, arc is generated between the pair of contact rings, and gas heated by the arc flows from the inside of an arc discharge space in a contact area into an annular heating chamber outside the contact area toward an outer side in the radial direction. When the arc is extinguished, pressurized gas accumulated in the heating chamber flows into the arc discharge space toward an inner side in the radial direction that is a direction opposite to the outer side in the radial direction, and further flows out to an exhaust chamber from the arc discharge space.